1. Field of the Invention
This invention relates to a copying apparatus, and more particularly to a copying apparatus which is capable of copying on both sides of a copy medium.
2. Description of the Prior Art
Heretofore, copying has usually been effected on one side of each copy medium. One-side copies quantitatively double both-side printed matter such as books or the like, and huge quantities of one-side copies cause storage and weight problems. Also, the recent trend to save materials and man power and to reduce the cost of copying has increased the need for copying machines which can effect copying on both sides of each medium.
There are copying machines of the transfer type which can perform copying on both sides of a copy medium. In these machines, conventional copying (including transfer and fixation) is first effected on one side of a copy paper, whereafter the same copy paper is directed back to the initial paper feed position or to a second paper feed means, from which the copy paper disposed upside down is introduced into the apparatus so that copying may be effected on the back side of the copy paper in the same way as is done on said one side. Such a system may be said to be practical in that it requires only one set of similar copying processes which leads to low cost and compactness of the copying machine.
When copying on both sides of a sheet of copy paper is desired, use may be made of an original carriage having an original supporting surface corresponding in dimensions to the combined area of two surfaces of one copy size in order to copy originals corresponding to both sides of a copy paper. In such case, two different originals may be placed on the original carriage at a time and copied alternately. This means a corresponding economy of the procedure for placement of originals on the original carriage (see FIG. 5 of the accompanying drawings).
Such case could be classified into the following two types.
1. Cases where the two originals to be copied on both sides of copy paper are separable and can be separately placed on the original carriage at a time.
2. Cases where the two originals to be copied on both sides of copy paper are not separable such as the opposite pages on a leaf of a book or the like and which cannot be placed on the original carriage at the same time.
Even in cases (2) above, if it is desired to copy a series of pages of a book (as would most usually be the case), the book may be opened and placed on the original carriage with the opened pages facing the respective original supporting surfaces of the carriage, and then copying may be carried out in the following sequence, for example:
In a first copy cycle, copying is effected on the back side of a first sheet of copy paper;
In a second copy cycle, copying is effected on the face of a second sheet of copy paper;
A leaf of the book is then turned over;
In a third copy cycle, copying is effected on the back side of the second sheet of copy paper;
In a fourth copy cycle, copying is effected on the face of a third sheet of copy paper;
A further leaf of the book is then turned over;
In a fifth copy cycle, copying is effected on the back side of the third sheet of copy paper;
and so forth. (See FIG. 5.)
Thus, in this case, two original surfaces placed on the original carriage are copied not on the opposite sides of the same copy sheet but on one side of a first copy sheet and the other side of a second copy sheet, respectively. In this case, however, it still holds true that the two original surfaces to be copied are placed on the original carriage at the same time.